Cesium-induced quantized 2D electron channel on the InAs(110) surface

We present the first clear evidence of electron emission arising directly from a quantized two-dimensional electron channel from the InAs(110) surface covered by a few Cs atoms (approximate to 0.01 Cs ML). Spectral features observed by photoemission spectroscopy using synchrotron radiation reveal discrete-energy electronic states resulting from quantization in the direction normal to the surface. The electron photoemission originates from the vicinities of Gamma points in the first and second surface Brillouin zones corresponding to the bottom of the conduction band. These findings are in agreement with self-consistent theoretical energy-level calculations using a jellium-like model.